Wood structure fabricating apparatus with magnetic hold-downs

ABSTRACT

Apparatus for holding wood members of a wood structure to be fabricated, such as the chord and web members of a wood truss, in position for being secured together at intersections between the wood members, as by driving nailing plates into the wood members from above and below. This apparatus comprises a plurality of stands for supporting the wood members at their intersection, and clamps for releasably clamping the wood members in position for being secured together by the nailing plates. The apparatus further comprises a magnetizable floor surface with at least one of the stands being readily movable on the floor surface to a desired position for supporting the wood members of the wood structure to be fabricated. This stand has one side thereof, facing generally outwardly of the truss, constituting the outside of the stand and has another side, opposite the one side, constituting the inside of the stand.

I United States Patent [1 1 Moehlenpah [4 1 Oct. 28, 19 75 WOOD STRUCTURE FABRICATING APPARATUS WITH MAGNETIC HOLD-DOWNS 22 Filed: Dec. 20, 1974 [21] Appl. No.: 534,753

[52] US. Cl... 269/321 F; 100/D1G. 13; 144/288 C;

. 227/152 [51] ,Int. C13... B23Q 3/02; B25l-l 5/00; B27F 7/02 [58] Field of Search 29/2; 227/152, 77;

144/288 R, 288 C; 269/321 R, 321 F, 17, 291, 305; 100/100, DIG. 13

3,358,589 12/1967 Hertzschel 144/288 C 3,421,751 1/1969 Menge 144/288 C 3,728,958 4/1973 Moehlenpah... 100/100 3,749,391 7/1973 Templin 269/321 F 3,752,467 8/1973 Stanley 144/288 C Primary Examiner-Othell M. Simpson Attorney, Agent, or FirmKoenig, Senniger, Powers and Leavitt [5 7] ABSTRACT Apparatus for holding wood members of a wood structure to be fabricated, such as the chord and web members of a wood'truss, in position for being secured together at intersections between the wood members, as by driving nailing plates into the wood members from above and below. This apparatus comprises a plurality of stands for supporting the wood members at their intersection, :and clamps for releasably clamping the wood members in position for being secured together by the nailing plates. The apparatus further comprises a magnetizable floor surface with at least one of the stands being readily movable on the floor surface to a desired position for supporting the wood members of the wood structure to be fabricated. This stand has one side thereof, facing generally outwardly of the truss, constituting the outside of the stand and has another side, opposite the one side, constituting the inside of the stand.

8 Claims, 6 Drawing Figures U.S. Patent Oct. 28, 1975 Sheet 1 of3 3,915,444

U.S. Patent Oct. 28, 1975 Sheet 2 of 3 3,915,444

Sheet 3 of 3 U.S. Pat ent Oct. 28, 1975 WOOD STRUCTURE FABRICATING APPARATUS WITH MAGNETIC HOLD-DOWNS BACKGROUND OF THE INVENTION This invention relates to apparatus for fabricating wood structures, such as prefabricated wood roof trusses or the like, and more particularly relates to such apparatus which holds the wood members in position to be secured together by nailing plates driven thereinto at the intersections or joints of the wood members.

Conventional wood truss fabricating apparatus utilize a plurality of stands adjustably movable independently of one another to positions corresponding to the intersections (i.e., the joints) of the wood members of the truss to be formed. Each time a new size or type of truss is to be fabricated on the apparatus, these stands must be moved to new positions so as to support the intersections of the wood members of the new truss to be formed. This rearrangement of the stands may have to be done several times a day as various truss sizes and configurations are fabricated.

As shown in US. Pat. No. 3,068,484, a line of stands is movable along a track for being selectively positioned at various locations along the lower chord of the truss to support the wood members at the joints of the truss. These stands may be releasably clamped to the track at any desired position therealong. Other stands slidable on the floor may be positioned along the upper chord of the truss and secured in a desired position by means of telescoping support links to the stands previously positioned along and clamped to the track.

Other apparatus, such as shown in US. Pat. No. 3,068,483, utilized a plurality of hydraulic presses, one for each joint of the truss. In one of the embodiments illustrated (FIGS. 30-32) some of these presses were mounted on stands having rollers which enabled the stands readily to be rolled to a desired. position on a steel floor plate. Such stands had an electromagnetic hold-down which permitted the stand to be held in position by energization of the magnet. While such a magnetic hold-down provided ready and infinitely variable positioning of the stands, it was found that once the stands were positioned and the electromagnets energized, the stands tended to rock outwardly varying amounts as the wood members were forcibly clamped and jigged to the stands (thus resulting in irregular trusses), and the stands tended to gradually slide horizontally during fabrication so that after a number of trusses had been fabricated, production would have to be halted and the stands repositioned. Thus, these magnetic hold-downs were not entirely satisfactory in securing the stand in its desired position.

SUMMARY OF THE INVENTION Among the several objects of this invention may be noted the provision of apparatus for fabricating wood structures in which at least some of the stands are readily adjustable to accommodate virtually any truss configuration and in which these stands may be readily and positively secured in any desired position; the provision of such apparatus which utilizes magnetic holddowns not adversely affected by irregularities in the magnetizable floor surface on which the stands are supr the stands from gradually horizontally sliding outwardly relative to the truss; and the provision of such apparatus whichis easy to use, reliable in operation and economical to manufacture. Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.

I Briefly, apparatus of this invention comprises a plurality of stands for supporting the wood members at their intersections, and means for releasably clamping the wood members in position for being secured together by nailing plates. At least one of the stands is readily movable on a magnetizable floor surface to a desired position for supporting the wood members of the wood structure to be fabricated. This stand has one side thereof, facing generally outwardly of the truss, constituting the outside of the stand and has another side, opposite this one side, constituting the inside of the stand. This stand further has a first horizontal axis of symmetry extending generally from the outside to the inside of the stand and a second generally horizontal axis of symmetry perpendicular to the first axis. The stand also includes means for supporting the stand comprising a pair of support legs, one on each side of the first axis, and engageable with spaced localized areas on the floor adjacent the outside of the stand. Means are provided on this one stand for lifting the stand clear of engagement with the floor surface for moving the-stand from one position to another. The stand also has selectively energizable electromagnetic hold-down means engageable with the floor surface for magnetically gripping the floor surface so as to positively hold the stand in a desired position on the floor surface and to resist forces applied by the wood members which tend to tip the stand outwardly relative to the wood structure. The hold-down means is positioned on the side of the second axis adjacent the inside of the stand so that with the stand supported on the floor surface by the magnet and by the support legs, the magnet, when energized, grips the floor surface and positively holds the stand in position thereon and effectively resists the tipping forces applied to the stand.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of apparatus of this invention for fabricating a-wood truss, the apparatus having a-plurality of adjustably movable stands;

FIG. 2 is an enlarged side elevational view taken on line 22 of FIG. I of one of the stands supporting a wood member; I

FIG. 3 is a front elevational view of the stand of FIG.

FIG. 4 is an enlarged bottom view of the stand;

FIG. 5 is a vertical cross sectional view taken on line 5-5 of FIG. 4;, and

FIG. 6 is an enlarged vertical cross sectional view taken on line 66 of FIG. 5 rotated with some of the parts broken away for clarity.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings, apparatus of this invention, generally indicated at 1, holds wood members W of a wood structure S to be fabricated in position for being secured together at the intersections of joints between the wood members. More particularly, apparatus l is shown holding thw web and the chord members 3 and 5, respectively, of a roof truss in position for being secured together by nailing plates 7 driven into the wood members at their joints from above and below by a hydraulic press (not shown) movable from joint to joint. The apparatus comprises a plurality of stands 9 for supporting the wood members at their intersections and for securely holding the wood members in position prior to being joined by nailing plates 7. Stands 9 have means, as generally indicated at 11 in FIG. 1, for releasably clamping the wood members in fixed relation to the stands in position for being secured together by the nailing plates. For example, clamping means 11 may be quick-release clamps as shown in U.S. Pat. No. 3,068,484 for clamping the wood members in position on the stands and enabling the completed truss readily to be removed from the stands.

Apparatus 1 further comprises a magnetizable floor surface 13 (e.g., a plurality of abutting steel plates) with stands 9 being readily movable thereon for movement to a desired position on the floor surface corresponding to the joints of a truss to be fabricated. Each of the stands which is movable on the magnetizable floor has first and second horizontal axes, as indicated at X-X and YY, respectively (see FIG. 4), which intersect at right angles to one another and which may generally be considered to be the axes of horizontal symmetry of the stand. With the stand positioned relative to the truss to be fabricated such that the adjacent chord member of the truss extends generally from one lateral side to the other of the stand (as shown in FIG. 1). The first axis XX extends generally from the front or outside to the back or inside of the stand and the second axis YY is generally perpendicular to the XX axis. While the wood member W in FIG. 4 is shown to be parallel to the YY axis, it will be understood that the wood members may be angled relative to the YY axis. A pair of support legs 14a, 14b are provided on the stand, one on each side of the XX axis. Each of these legs is engageable with a small, localized area of floor 13 immediately therebelow and constitutes means for supporting the stand. Lifting means, or more particularly roller means, as generally indicated at 15, are provided on each stand, these roller means being movable between a lowered extended position (see FIGS. 5 and 6) in which the roller means are in rolling engagement with magnetizable floor 13 and the stand is lifted clear of the floor for permitting the stand readily to be rolled from one position to another, and a raised retracted position (as shown in FIGS. 2 and 3) in which the stand is in engagement with the floor. It will be understood that other means, such as an airlift system as shown in U.S. Pat. No. 3,728,958, may be used to lift the stands for movement and repositioning.

It is important, when assembling the wood members W preparatory to nail plate pressing, that there by tight abutment between each of the wood members at the joint. To accomplish this the web members of the truss to be formed are forced into position, sometimes by hammering, so that there are substantial forces exerted outwardly of the truss which tend to tip the stands away from the truss. Because of slight dimensional variations in the wood members, these outward forces on the truss may vary from truss-to-truss. Also, frequently, as clamped preparatory to nail plate pressing, the assembled truss members are further prestressed to bow the bottom chord slightly upwardly to effect a preset camber in the truss, so that after completion and subject to the expected structural loads imposed, the truss chords will be straight. This, if course, further increases the net outward forces on the stands.

The stand also includes magnetic hold-downs, generally indicated at 17, which are engageable with floor 13 and which magnetically grip the magnetizable floor so as to positively hold or clamp the stand in any desired position on the steel floor and to effectively resist these forces applied to the stand which tend to tip the stand outwardly relative to the truss. Hold-downs 17 are shown to comprise at least one and preferably a pair of selectively energizable electromagnets 19a and 19b. As shown in FIG. 4, magnets 19a, 19b are on opposite sides of axis XX and both of the magnets are on the side of axis YY adjacent the inside of the stand (i.e., toward the truss). This is particularly important because with roller means 15 in their raised retracted position and with the stand supported on floor 13 by legs 14a, 14b at the outside of the stand and by magnets 19a, 19b at the inside of the stand, the magnets, when energized, magnetically grip the floor to positively hold the stand in position and to resist the tipping forces exerted on the stand.

More particularly, each stand 9 movable on magnetizable floor 13 includes a rigid frame having spaced, vertical side members 21, a base 23, members 25 for supporting the wood members on the stand, and a locator plate 27 below members 25 for holding a lower nailing plate. This locator plate is movable upwardly toward the wood members by the press to drive the lower nailing plate into wood members from below. Horizontal braces 29 span the space between the wide members and the various parts are secured together, as by welding. But for details of base 25, stand 9 is generally similar to the stand shown in the above-mentioned U.S. Pat. No. 3,068,484. Reference may be made to this patent for further details of the stands, and the above-mentioned hydraulic press movable from stand to stand for driving nailing plates into the wood members. As shown in FIG. 4, stand base 25 includes the base plates 31a, 31b at the ends of the stand extending parallel to the XX axis and braces 33a, 33b at the front and back of the stand, respectively, extending parallel to the YY axis. As best shown in FIGS. 4 and 6, legs 14a, 14b are hollow and are secured, as by welding, to base 25. A third leg 35 essentially identical to legs 14a, 14b is positioned on the XX axis adjacent the inside of the stand is also welded to base 25. These legs are of square cross section hollow metal tubing or the like. More particularly, legs 14a, 14b are respectively secured to base plates 31a, 31b on opposite sides of axis XX at the front or outside of the stand and leg 35 is secured to brace 33b at the back of the stand on axis XX. As shown in FIG. 6, magnets 19a, 19b are adjustably secured to base 25 by bolts 36. Preferably the bottom faces of the magnets are positioned at or slightly below the bottoms of legs 14a, 14b and leg 35 so as to insure that the magnets engage floor 13, even if the floor is wavy.

Roller means 15 are shown to be ball caster units, such as manufactured by the Matthews Conveyor Company of Ellwood City, Penn., having a ball roller 37 free to rotate about any axis thereby permitting the stand freely to be moved in any direction on floor 13. As shown in FIG. 6, each ball roller 37 is mounted in a caster housing 39 (of generally circular cross section).

A generally square cross section guide block. 40 is secured to the upper end of housing 39 and the caster housing and the guide block are movable vertically within their respective legs 14a, l4b and 35 between an extended position (seeFIG. 6) corresponding to the above-mentioned lower extended position of roller means in which ball roller 37'extends below its respective leg and engages floor 13 and a' raised position in which the ball roller is clear of the floor. This lastmentioned position corresponds to the above-- mentioned raised retracted position of roller means 15. With the rollers retracted, it will be understood that stand9 is supportedon floor l3 by legs" 14a, 14b and by magnets 19a, 19b since the magnets and these legs are located on opposite sides of the center of gravity of the stand (which is located near the intersection of the XX and Y-Y axes), and since'the magnets preferably extend slightly below the plane established by'the bottoms of legs 14a, I45 and In this manner, contact of the'mag'nets with floor 13 is insured regardless of unevenness or waviness of the floor. Thus, air gaps between the bottom" faces of the magnets and the floor are minimized andmag nets 19a, 19b exert their maximum available gripping force on floor'13.

Each ball roller 37 is raised'and lowered relative to its respective leg 14a, 1411101 350 by means of a camoperated linkage arrangement generally indicated at 41 for effecting simultaneousr'novern'ent of the rollers between their raised retracted' and lower extended positions. This linkage arrangement is shown to comprise a shaft 43 joumalled in guide blocks of the front caster units. Openings 44 (see FIG. 5) in the sides of legs 14a and -l4b surround shaft 43, 'these openings being substantially larger than the diameter of the shaft. Cams 45 are carried by the shaft adjacent legs 14a and 14b, and are engageable with stationary cam followers 46 secured to the legs and the base 25 of stand 9'adjacent openings 44. Upon rotation of shaft 43 in one direction (i.e., clockwise as yiewed in FIG. 6), cams 45 engage their respective cam followers 46 and cause the shaft .to move down relative to openings 44 thus effecting relative movement between guide blocks 40 and legs 14a and 14b so as to effect movement of the rollers from their raised retracted to their lowered extended positions. With the rollers in their lowered extended positions, it will be understood. that the weight of the stand is carried by cams 45. As is best shown in FIG. 6, cams 45 have flats 47 thereon engageable with their cam followers 46 when the rollers are in their lowered extended position thereby to positively maintain the rollers in their lowered extended positions. A stubshaft 48 is joumalled in guide block 40 ofthe roller in rear leg 35, this stubshaft'extending sidewise of the leg 35 through enlarged openings 44 there. Like shaft 43, Stubshaft 48 carries earns 45 on the outside of leg 35 engageable with stationary cam followers 46. Stubshaft 48 is interconnected to shaft 43 by means of cranks 49 and 50 secured to shaft 43 and stubshaft 48, respectively, and by a link 51 pinned between the ends of the cranks. Thus, upon rotation of shaft43, via crank handle 53, the rollers in front leg 14a and 14b are caused to move with the shaft and the roller in rear leg 35 is moved simultaneously therewith between their raised retracted and lowered extended positions.

It will be noted that the previously mentioned outward forces applied to stands 9 by the jigged and clamped wood members W of the truss S tend to cause at least some of these stands to tip outwardly and rotate a about the outer edges of front legs 14a and 14b and tend to cause magnets 19a, 19b to lift off floor 13. Under normal operating conditions in which floor 13 is clean and free of grease or other contaminants which tend to decrease the coefficient of friction of the floor, the friction of legs 14a, 14b bearing on the floor is sufficient to resist the horizontal forces exerted on the stand by the jigged and clamped wood members. However, under other conditions, such as when floor 13 is dirty, the friction of the outside legs on the floor may not be s ufficient to entirely resist the horizontal forces on the stand. It is in these situations where the advantages of the present invention become most apparent.

More particularly, with magnets 19a, 19b located adjacent the inside of stand 9, it is seen that they are distal from the outer edges of legs 14a, 14b (about which the stand tips). minimizes the vertical restraining forces required to be exerted by the magnets to prevent the stands from tipping and thus maximizes the bearing force (and hence the friction) of the magnets on the floor. The frictional force between the magnets and the floor and the frictional force between legs 14a, 14b and the floor is sufficient to resist the horizontal forces applied to the stand by the jigged and clamped wood members even under adverse operating conditions. Thus, the necessity to periodically halt production of trusses to reposition the stand is eliminated.

Also, with stand 9 supported by legs 14a, 14b at the outside of the stand and by magnets 19a, 19b at the inside of the stand, and with the magnets gripping the floor, rocking movement of the stand on the magnets is prevented. In prior art stands with magnetic holddowns, such as shown in my previously mentioned US. Pat. No. 3,068,483, under certain conditions (i.e., floor waviness), the stand was supported solely by the magnet with the remainder of the stand clear of the floor. Thus, upon clamping and jigging wood members W in place, these prior art stands could rock on the magnets until the outer portions of the stand again engaged the floor. This rocking movement of the stand could cause the top of .the stand to move, appreciably (.g., 0.25 inch or 0.62 mm.) thus causing irregular or out-oftolerence trussesto be fabricated on the apparatus. In

\ the present invention, with the stand supported by mag- I nets 19a, 1% at the inside of the stand and by legs 14a,

I411 at the front of the stand, the stand is never supported solely by the magnets, and thus rocking of the stand on the magnets is prevented.

Power is supplied to electromagnets 19a, 19b .by power cables 55 (see FIG. 1). A switch 57 (see FIG. 3) on each stand 9 selectively energizes and de-energizes electromagnets 19a, 19b on the stand. Thus, with the stand positioned in its desired location on floor 13, it may readily be locked to the floor simply by throwing switch 57. 1

A guide rail 59 (see FIGS. 1, 2 and 5) may be secured to floor 13 to aid in aligning a row of stands 9 along a straight line, as it may be desired to align stands along the lower chord of a truss. With the outer faces of legs 35a, 35b of each stand in engagement with rail 59, the alignment of the lower chord stands is insured,

It will be understood that not all stands 9 of an apparatus of this invention need be equipped with magnetic hold-downs. For example, in apparatus similar to that shown in the above-mentioned US, Pat. No. 3,068,484, only the stands supporting the upper chords have magnetic holddowns as the stands along the lower chord may be adjustable movable along and clamped to their guide track. Also, this invention may be utilized in apparatus similar to the apparatus shown in U.S. Pat. No. 3,068,483 in which each stand carries a hydraulic press for driving the nailing plates into the wood members at each joint.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Apparatus for holding wood members of a wood structure to be fabricated, such as the chord and web members of a wood truss, in position for being secured together at intersections between the wood members, as by driving nailing plates into the wood members from above and below, said apparatus comprising a plurality of stands for supporting the wood members at their intersections, and means for releasably clamping the wood members in position for being secured together by said nailing plates, said apparatus further comprising a magnetizable floor surface with at least one of the stands being readily movable on the floor surface to a desired position for supporting the wood members of the wood structure to be fabricated, said one stand having one side thereof facing generally outwardly of the truss constituting the outside of said stand and having another side opposite said one side constituting the inside of said stand, said one stand having a first horizontal axis of symmetry extending generally from the outside to the inside of the stand and a second generally horizontal axis of symmetry perpendicular to the first axis, means for supporting the stand including a pair of legs, one on each side of the first axis and engageable with respective spaced localized areas of the floor adjacent the outside of the stand, means for lifting the stand clear of engagement with the floor surface for moving the stand from one position to another, and selectively energizable electromagnetic hold-down means engageable with said floor surface for magnetically gripping said floor surface so as to positively hold the stand in a desired position on the floor surface and ping forces applied to the stand.

2. Apparatus as set forth in claim 1 wherein said hold-down means comprises a pair of electromagnets adjacent the inside of said stand, one on each side of the first axis.

3. Apparatus as set forth in claim 2 in which said lift-. ing means comprises roller means movable from a lowered extended position in which they extend below the supporting means and said magnets for engagement with said floor surface thereby to lift the stand clear of the floor surface for moving the stand from one position to another and a raised retracted position in which the supporting means and said magnets are in engagement with the floor surface.

4. Apparatus as set forth in claim 3 wherein said supporting means includes a third leg located on said first axis adjacent the inside of the stand.

5. Apparatus as set forth in claim 4 wherein each of said legs is hollow, said roller means being located within said hollow legs for movement between their stated lowered extended and raised retracted positions.

6. Apparatus as set forth in claim 5 further comprising linkage means interconnecting said roller means for effecting simultaneous movement of said roller means between their lowered extended and raised retracted positions.

7. Apparatus as set forth in claim 3 wherein said roller means are ball rollers rotatable about any axis for permitting said one stand to be moved in any horizontal direction on said floor surface on said rollers when the latter are in their lowered extended position.

8. Apparatus as set forth in claim 1 further comprising 'a plurality of stands similar to said one stand whereby said stands are readily repositioned on said floor surface so as to permit the ready fabrication of wood structures of various configurations. 

1. Apparatus for holding wood members of a wood structure to be fabricated, such as the chord and web members of a wood truss, in position for being secured together at intersections between the wood members, as by driving nailing plates into the wood members from above and below, said apparatus comprising a plurality of stands for supporting the wood members at their intersections, and means for releasably clamping the wood members in position for being secured together by said nailing plates, said apparatus further comprising a magnetizable floor surface with at least one of the stands being readily movable on the floor surface to a desired position for supporting the wood members of the wood structure to be fabricated, said one stand having one side thereof facing generally outwardly of the truss constituting the outside of said stand and having another side opposite said one side constituting the inside of said stand, said one stand having a first horizontal axis of symmetry extending generally from the outside to the inside of the stand and a second generally horizontal axis of symmetry perpendicular to the first axis, means for supporting the stand including a pair of legs, one on each side of the first axis and engageable with respective spaced localized areas of the floor adjacent the outside of the stand, means for lifting the stand clear of engagement with the floor surface for moving the stand from one position to another, and selectively energizable electromagnetic hold-down means engageable with said floor surface for magnetically gripping said floor surface so as to positively hold the stand in a desired position on the floor surface and to resist forces applied by the wood members to the stand which tend to tip the stand outwardly relative to said wood structure, said hold-down means being positioned on the side of said second axis adjacent the inside of the stand so that with said stand supported on said floor surface by said hold-down means adjacent the inside of the stand and by said legs adjacent the outside of the stand, said hold-down means, when energized, grip said floor surface and positively hold the stand in position thereon and effectively resist said tipping forces applied to the stand.
 2. Apparatus as set forth in claim 1 wherein said hold-down means comprises a pair of electromagnets adjacent the inside of said stand, one on each side of the first axis.
 3. Apparatus as set forth in claim 2 in which said lifting means comprises roller means movable from a lowered extended position in which they extend below the supporting means and said magnets for engagement with said floor surface thereby to lift the stand clear of the floor surface for moving the stand from one position to another and a raised retracted position in which the supporting means and said magnets are in engagement with the floor surface.
 4. Apparatus as set forth in claim 3 wherein said supporting means includes a third leg located on said first axis adjacent the inside of the stand.
 5. Apparatus as set forth in claim 4 wherein each of said legs is hollow, said roller means being located within said hollow legs for movement between their stated lowered extended and raised retracted positions.
 6. Apparatus as set forth in claim 5 further comprising linkage means interconnecting said roller means for effecting simultaneous movement of said roller means between their lowered extended and raised retracted positions.
 7. Apparatus as set forth in claim 3 wherein said roller means are ball rollers rotatable about any axis for permitting said one stand to be moved in any horizontal direction on said floor surface on said rollers when the latter are in their lowered extended position.
 8. Apparatus as set forth in claim 1 further comprising a plurality of stands similar to said one stand whereby said stands are readily repositioned on said floor surface so as to permit the ready fabrication of wood structures of various configurations. 